Honesty may boost your health, suggests a study that found telling fewer lies benefits people physically and mentally.

Each week for 10 weeks, 110 individuals, ages 18-71, took a lie detector test and completed health and relationship measures assessing the number of major and minor lies they told that week, says lead author Anita Kelly, a psychology professor at the University of Notre Dame in Indiana. She presented findings at the annual meeting of the American Psychological Association, which ended Sunday.

"When they went up in their lies, their health went down," says Kelly. "When their lies went down, their health improved."